1. Field of the Invention
The present invention pertains to the art of two-compartment refrigerators in which a portion of the air being circulated in one compartment is diverted, through a partition wall, into the other compartment and, more particularly, to a mechanism which controls the temperature in each compartment and the flow of air between the two compartments.
2. Discussion of the Prior Art
In two compartment refrigerators, air is generally circulated over an evaporator and then delivered to both a freezer compartment and a fresh food compartment. Typically, two user operated temperature controls are provided. One control member is for controlling the freezer compartment temperature, while the other control member controls the fresh food compartment temperature. The fresh food control is operatively connected to a thermostat unit that senses the temperature in the fresh food compartment by means of a capillary tube routed from the thermostat unit to the fresh food compartment. With this arrangement, the fresh food control thermostatically maintains the fresh food compartment temperature by periodically energizing and de-energizing a compressor of a refrigerator circuit.
The freezer control is connected to an air flow damper positioned in a passageway which delivers air from the freezer to the fresh food compartment. As the freezer control is set to a colder position, the damper is moved to allow less air into the fresh food compartment and the fresh food control responds by increasing the active time of the compressor to maintain the temperature in the fresh food compartment and thereby indirectly cools the freezer compartment. Conversely, if the freezer control is set to a less cold position, the damper moves to allow more air to be sent from the freezer to the fresh food compartment and once again the fresh food compartment control compensates by running the compressor less often. A major disadvantage associated with such a known arrangement is that the fresh food and the freezer controls are not independent. For example, when only the fresh food control is adjusted, the temperature in the fresh food compartment will change as expected but the freezer compartment temperature will also change significantly.
One proposed solution to this problem is to incorporate multiple temperature sensors (see U.S. Pat. No. 5,385,032). More specifically, one capillary tube would be routed from the controls to the freezer compartment and a separate capillary tube would be routed from the controls to the fresh food compartment. However, such an arrangement adds a tremendous cost to the refrigerator because of the difficulty involved in routing the capillary tubes. Another approach is to add multiple independent baffles. One set of baffles would be controlled normally by the freezer control, while another set of baffles would be regulated by an additional control circuit to provide a compensation airflow based on both the fresh food control and the freezer control (see for example U.S. Pat. Nos. 4,009,589, 4,009,590, and 4,009,591). This approach also adds tremendous cost to a refrigerator, not only in the cost of parts but also the necessary time for assembly.
Therefore, there exists a need in the art for a mechanism to control the flow of air between two compartments in a refrigerator which does not require the use of multiple capillary tubes or baffles, is easy to assemble and minimizes associated routing costs.